As an example of an electricity storage device, an electric double layer capacitor has been developed as an electricity storage device for power assistance, backup, or the like of an electronic device. In the development of the electricity storage device, an electricity storage unit made by combining a plurality of capacitors has been considered.
FIG. 13 is a perspective view illustrating a conventional capacitor module as an example of a conventional electricity storage unit. The conventional capacitor module has lower case 101, upper case 102, connector 103, and screw 104. Lower case 101 and upper case 102 house a plurality of capacitors and a control board electrically connected with these capacitors (both are not shown) so as to hold the capacitors and the control board from above and below. Connector 103 is exposed to outside from lower case 101 and upper case 102. Screw 104 fixes upper case 102 to lower case 101 at each end parts of lower case 10 land upper case 102.
It is noted that, for example, Unexamined Japanese Patent Publication No. 2009-253009 1 is known as a prior art document regarding the present application.